%I #10 Jun 09 2016 08:38:30
%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,
%T 26,27,28,29,30,31,32,33,34,35,37,36,38,39,40,41,42,43,44,45,46,47,48,
%U 49,50,51,52,53,54,55,57,58,59,56,60,61,70,62,71,72,73,74,75,77,78,79
%N Pick any pair of "6" digits in the sequence. Those two "6"s are separated by k digits. This is the lexicographically earliest sequence of distinct terms in which all the resulting values of k are distinct.
%C The sequence starts with a(1)=0. It is then always extended with the smallest integer not yet present and not leading to a contradiction (which would mean producing a value of k already seen).
%H Eric Angelini, <a href="/A273884/b273884.txt">Table of n, a(n) for n = 1..1011</a>
%Y See A273376 for the equivalent sequence dealing with digit-"1" pairs instead of "6"
%K nonn,base
%O 1,3
%A _Eric Angelini_ and _Jean-Marc Falcoz_, Jun 02 2016